1. Field of the Invention
This invention relates to a pressure vessel and more particularly to inexpensive pressure vessels which may be disposed of rather than repaired when they fail.
2. Description of the Prior Art
Pressure vessels refer to rigid vessels, some of which have an expandable inner chamber which is usually filled with a gas and an outer chamber which is subjected to the influx of hydraulic oil. The purpose of the dual chambers is to allow the incoming oil to be buffered to a certain extent before the oil is withdrawn for use within a hydraulic system. Normally such pressure vessels can be used in seat suspension systems and the like. In the past, disposable pressure vessels or accumulators as they are sometimes called, typically demanded a squeeze on the inner liner or bladder to seal the gas and the fluid of the pressure vessel from the atmosphere. In order to accomplish this sealing, threaded or row connections were used but proved to be very expensive. Pulsation in flexing forces in the bladder tended to generate leakage when the seal was dependent on squeeze. Although continuous bead welding provided an acceptable seal from the atmosphere, there did remain a difficult process of preventing thermal damage to the bladder during the manufacturing process.
One prior art patent which sought to overcome these deficiencies was U.S. Pat. No. 4,177,836 issued to Thompson on Dec. 11, 1979 and assigned to Deere & Co. The Thompson patent sought to seal the bladder to the pressure vessel without the need for a welded connection. Such a design proved to be beneficial but necessitated costly machining of certain components such as the cylindrical housing and the end cap. Now, a pressure vessel has been invented which combines the welded joint with a unique sealing arrangement for preventing internal damage to the bladder.
The general object of this invention is to provide a pressure vessel. A more specific object of this invention is to provide a disposable pressure vessel which may be disposed of rather than repaired when it fails.
Another object of this invention is to provide a pressure vessel which is inexpensive and easy to assemble.
Still another object of this invention is to provide a pressure vessel having a sealable joint in combination with a welded joint wherein the sealed joint is not thermally effected by the welding process.
A further object of this invention is to provide a pressure vessel having a positive gas and fluid seal while reducing the mnufacturing cost.
Other objects and advantages of the present invention will become more apparent when considered in connection with the following description and the drawing.